Sign holder



FIG. 1 is a front, top and right side perspective view of a sign holder showing my new design;

FIG. 2 is a rear, bottom and left side perspective view thereof;

FIG. 3 is a front, top and right side perspective view of a transparent marking sleeve with a sign pocket forming a variant of my design; and,

FIG. 4 is a rear, bottom and left side perspective view thereof. 

The ornamental design for a sign holder, as shown and described. 